BIOSCIENCES BIOTECHNOLOGY RESEARCH ASIA, December 2024. Vol. 21(4), p. 1671-1681 Published by Oriental Scientific Publishing Company © 2024 This is an Open Access article licensed under a Creative Commons license: Attribution 4.0 International (CC-BY). *Corresponding author E-mail: sajithamenonk@gmail.com Diversity, Extracellular Enzyme Activity and Growth Promoting Potential of Fungal Isolates from the Roots of Coleus aromaticus Benth. Sajitha Menon Kampurath 1 *, Sneha Poongodu Velayudhankutty 1 and Renju Krishna Valsamma 2 1 Department of Botany, Government Victoria College, Palakkad, Kerala, India. 2 Department of Botany, Mercy College, Palakkad, Kerala, India. https://dx.doi.org/10.13005/bbra/3335 (Received: 25 September 2024; accepted: 29 November 2024) Coleus aromaticus Benth. a member of Lamiaceae family is a herbaceous plant with numerous medicinal properties. The present study was aimed at the isolation, characterization, extracellular enzyme activity and growth promoting ability of endophytic fungi from the roots of C. aromaticus collected from different parts of Palakkad, Kerala, India. A total of nine cultures grouped into five morphotypes including one non-sporulating taxa mostly belonging to Ascomycota were isolated. Their colonization rate and diversity index was determined. Extracellular enzyme activity and plant growth promotion studies were also carried out. Amylase activity was exhibited by all isolates, while none of them showed tyrosinase, protease, or laccase activity. Among the isolates, Fusarium sp. exhibited significant root and shoot length promotion in Vigna radiata seedlings, and its identification was confirmed through sequence analysis as Fusarium solani. The results indicated that the endophytic association has a positive role in promoting plant growth and revealed diverse mycoflora in the roots of Coleus aromaticus with various biological activities, highlighting the potential for further research into endophytes and their metabolites as a promising field. Keywords: Coleus aromaticus; Extracellular Enzyme Activity; Fungal endophytes; Lamiaceae; Plant growth promotion. Endophytic fungi are a unique group of organisms that reside within various tissues and organs of terrestrial and certain aquatic plants. These fungi establish infections that often go unnoticed, as the host tissues remain symptomless, at least temporarily 1 . Endophytic fungi are known to engage in mutualistic interactions with their host plants, primarily by enhancing the host’s resistance to herbivores 2 . In most cases, fungi benefit from colonizing a plant host as they gain access to nutrients and protection from various abiotic stresses. Previously, mutualistic symbiosis was primarily associated with mycorrhizal fungi residing inside plant roots. However, it has been recently discovered that many other fungi, especially endophytic fungi, can also engage in mutualistic root symbioses 3 . Endophytic fungi, throughout most or all of their life cycle, inhabit plant tissues without causing visible symptoms. This diverse group of fungi includes dormant saprophytes and latent pathogens, occupying different habitats and positions in the food chain